Purification of synthetic peptides using reversible chromatographic probes based on the Fmoc molecule

A rapid, versatile, reversible procedure for purifying synthetic peptides has been developed based on the specific incorporation of 4‐carboxylate Fmoc derivatives onto the terminal amino acid of peptidyl‐resins. The acid stable 4‐COR‐Fmoc derivatives were synthesised with a variety of chemical groups thus altering the chromatographic properties of the “target” peptides and permitting their convenient purification, either by reversed‐phase HPLC or ion exchange chromatography. The assembly of the peptides involved a capping step to prevent the formation of deletion forms. The 4‐COR‐Fmoc derivatives were incorporated either as preformed amino acid conjugates or as activated succinimidyl esters. After HF cleavage and purification the 4‐COR‐Fmoc probes were quantitatively removed with organic bases. The efficiency of the technique was demonstrated by the purification of small to large sized peptides, including a cyclic analogue.